Telephone-exchange system



March 1 1927.

B. G. :mlm-wvll TELEPHONE EXCHANGE SYSTEM 8 Sheets-Sheet4 `ld@ .N SQ

March 1 1927.

B. G. DUNHAM TELEPHONE EXCHANGE SYSTEM Filedoct. 1e. 1925 8 Sheets-Sheet 2 March 1 1927. 1,619,250

B.AG. DUNHAM `TELEPHONE EXCHANGE SYSTEM Filed oct. le, 1925 8 Sheets-Shet 5 ffy. 3;

. //7 Ven/0r:

March 1, 1927. 1,519,250

v B. G. DUNHAM r TELEPHONE EXCHANGE SYSTEM y Filed Oct. 16, 1925 l8 Sheets-skelet' 4 March l 1927.

TELEPHONE EXCHANGE SYSTEM YFiled oct. 1e,.1925 s sheets-sheet 5 Mach l 1927.

- 1,619,250 B. G. DUNHAM TELEPHONE EXCHANGESYSTEM Filed Oct. 16, 1925 8 sheets-sheet e //7 Ven/0f.' 5e/f G. a/Mam.

B. G. DUNHAM Y TELEPHONE EXCHANGE SYSTEM.

Ma^rh1,1927.. I 1,619,250

Filed oct. 1e, 1925v 8 sheets-sheet f March 1 ,1927, 1,619,250

l B, G. DUNHAM TELEPHONE EXCHANGE SYSTEM Filed ocx. 16, 1925 s sheets-sheet a Patented Mar. 1, `19.27.

Unirse stars esta..A

BERT G. DUNHAM, F HAVTI-IORNE, NEVI' JERSEY, ASSGNGR. T0 VESTERN ELECTRIC COMPANY,INCORPORATED, OF NEW/V YORK, N. Y.,'A CORORATION OF NEW YORK- TELEPHONE-EXCHANGE SYSTEM.

application fusa october 16.1925. serial no. 62,725.

This invention relates to telephone eX- change systems for interconnecting subscribers at manual and automatic oflices, and

more particularly to systems of the step-bystep type.

rlhe object of the invention is the provision of improved cordless B circuits whereby an operator ata manual office is connected to a cordless B7 operator in an automatic oiiice who receives the number to which connection is desired directly over the trunk to the manual office, and controls the setting of switches Ain which the trunk terminates to establish the connection.

A feature of the invention is the provision of a counting relay arrangement employing a smaller number of pairs of relays than the maximum number 'of impulses to becounted, including optional pairs of'r-elays and means for choosing between said. optional pairs `dependent upon the number of impulses to be counted.

A further featurev ofthe invention is the employment of the sen-der circuit as either a four digit or a five digit sender. The sender circuit is provided with a relay which is operated if the first or thousands digit has certain numerical values to delay the disconnection from the link circuit until after `a fifth digit has been registered and sent. If this relay is not operated the sender is dismissed after the sending of four digits.

' A further feature lof the invention lies in the provision of means for restoring the sender to normal and resetting the registers without disconnecting the sender from the link. This method of control makes it possible forthe B operator to reset the regisy ters in case a mistake has been made in setting up one or more of a series of digits.

A further feature 'of the invention is the combination link and control circuit to establish a straightforward trunlring circuit between A and B operators positions as well as to establish switch control circuits from the sender to switches associated with the trunk.

Fig. 1 shows diagrammatically a calling subscribers substation connected to an answering jack and a cord circuit at an A operators position in a manual ofHce, and

further shows in detail an outgoing trunk jack associated with a trunk circuit in the called oiiice, also the first selector of the called office enclosedV by the broken line.

Figs. 2, t and 5 show the link circuit comprising a trunk finder circuit (Fig. 2), a position selector (Fig. 5), and a sender selector (Fig. 4).

Fig. 3 shows a position circuit for a cordless B 'operator to enable such operator to talk with the manual A operator over a connection established through the link circuit, and to set the selected sender by means of a keyboard sender.

Figs. 6, 7 and 8 constitute the B operators sender circuit, Fig.r 6 showingthe transfer relays, Fig.. 7 the register relays, and Fig. 8 the six pairs `of counting relays. Fig. 9 shows the relative positions of drawings 1 to 8.

VThe system disclosed as embodying the present invention will be best understood from a description of the operati-on thereof taken in conjunction with the accompanying drawings.

A manual subscriber 100 upon lifting the receiver from the hook lights a line lamp at the A operators position in the well known manner whereupon the A operator plugs into the answering jack and receives the number desired. rlhe A operator by means Vo-fhercord circuit 103 connects the manual calling subscriber 100 to a trunk 'outgoing to the called office by plugging into outgoing trunk jack 104. Villen the manual operator plugs into the jack 101i associated with trunk conductors 105 and 106, relay 107 operates over the trunk loop in a circuit which may be traced from ground through f the right winding of relay 107, right back contact of relay 109, right normal contact of relay 110, upper left winding of repeating coilV 111'to the tip of jack 104,V tip of plug 112 through the usual polarized relay (not shown) of the cord circuit 103, ring of plug 112r and jack 1041, conductor 10G through the lower left winding of repeating coil 111, left normal contact of relay 110, left back contact of relay 109, left winding of relay 107 to battery. The operation of relay 107 in. turn operates relay 108 in a circuit from ground at the right lront contact ot relay 107 through the Winding of relay 10S to battery and ground.

The operation ot relay 10S closes the circuit for starting the trunk Atinder by connecting ground to group start lead 113; Relay 200 operates in a circuit which may he traced 'from ground at the right baci;

contact oli relay 114, right front contact ot relay 10S, conductor 113, through norn'ially closed eroe J start he f 201 windine of relay b v o `lay 210, middle right haelt contact of relay #142, upper normal contact of key Q40, to ground` at the ri glit Contact oi relay 200.

Relay Q02 operated `closes an operating path for relay 203 which may be traced from grounded battery, right iiilnding ot' relay Q03, armature and closed contact of rotary magnet 208, cloned contact and armature ot Vertical magnet E200, conductor 228, contact ot relay E302 to grounded Contact ot relay 210. Relay 202 operated also closes a start lead to the link circuit at its middle front contact, and opens a short circuit between leads 9.04, E205 at its outermost lett back contact.` Relay 203 operated energizes the yertical magnet Q00 inl a circuit which may be traced from grounded battery through the winding of vertical magnet 20G, lett back contact ot relay E207 to grounded contact ot relay :203. The trunk finder switch takes one vertical step, thus breaking the energizing path :torrelay Q03; lelay 203 will accordingly release and allow yerticalinagnet 200 to release as Well. Magnet 20G having released, relay Q03 will again energize and the trunl; inder switch will take another vertical Step. Thi@` action will continue until the connnutator brush 116 connects to grounded commutator segment 115. Relay 2053 will be held operated 'and relay Q07 Will operate in a circuit which may be traced` from grounded battery through the right Winding ot relay 203, arn'iature and contact ot rotary magnet 20S, conductor 209, lett winding of relay 207, next to the innermost lett back contact ot relay Q10, conductor Q30, connnutator brush 110, coiumutator segment 115, conductor i231 to ground at the lett trontcontact ot relay i200; The operation of relay 207 opens the energizing circuit of vertical magnet 200 allowing it to release, and causes` rotary magnet i208 to operate .in va circuit which may he traced from grounded battery through the winding of rotary magnet 208, conductor 232, lett front contact and armature of relay Q07 to grounded contact ot relay 20?. The trunk linder switch thereupon takes one rotary step. Rotary magnet 208 causefs relay Q03 to :tuna-tion the saine ae did .f'ertical ste]L ping magnet Q00 and the Switch Will continue to telic rotary steps until the traneler coiuluctor E211 connecte to the contact which is connected to battery through relay 109 oi the trunk circuit. 'l`liereupon relay Q03 will he held energized in a circuit which may he traced .troni groinid through the lett winding oiE relay i210, through the le'lit winding ot relay E203 in sse-ricau outer 'trout Contact oilt relay it), conductor i211. brush Q35, contact 118, teet coinluctor 117. lelft back contact ot relay 111i, lett contact o't' relay 1053, winding oit relay 100 to grounded battery. llclay 210 will energize in this circuit and lock to ground through the onoruial contact 2l?. in a circuit which may he traced 'troni grounded battery through the right Winding of relay 210.` lclt 'front Contact ot that relay, to ground at oil-normal contact 212. The operation ot relay Q10 will connect direct ground 'troni the innermost grounded armature ol that relay to test lead 211 and will open the energizing circuit et relay i207 at its le'lt innermost back contact. llelay 207 releaeee` and extends th start eircuit to the next idle trunk tinder. The extended start circuit may be traced Alroin ground at the right ci'intact ot relay 200, intermediate normal contact ot ltey 240, middle right back contact ot relay 442, iniddle lett front contact ol relay 210, ri glitbaclz contact ot relay 207, inner right haelt contact oilI relay klfl, upper normal contact oit, ltey 2110 thence to the out start wire connected to thi contact ot key 2&0. llelay 210 operated` riesce` a circuit tor operatingrelay 213 which may he traced troni grounded battery through the winding ot relay Q13, iunerinoat Yl'ront contact ol relay 202 to the iiiterniediate grounded arnrature oi? relay 2l0. The operation ot relay 210 also opens the coni-A inntator brush circuit traced hereinabove and cloffsea a chain relay circuit' at its lclt iront innermost contact and armature which torina a part ol an all-linders-busy circuit. rl`he operation oi relay Q13 at this time connects the talking leads ot the trunk through to the link, closes the pulsing leads over which the switches are to be operated in reaching the Yanted number, opens the rcleaee magnet circuit and partially closes a short circuiting path across leads 201i, 205

lill

of relay 202` innermost grounded contact ot relay 210. The operation ot relay 109 causes the release of relays 107 and 108. Relay 109 vperated, locks to test lead 117 in a circuit which may be traced from grounded battery, winding olf' relay 109, left front contact ot relay 109, conductor 120, left back contact ot relay 114 to ground on test lead 117.

As soon as the trunk finder switch tool: one step, relay 400 Was operated in a circuit which may be traced from grounded battery, Winding of relav 400, conductor 402, oltnormal contact 229 to ground at neXt to the outermost lett back Contact of relay 210.

- The operation ot relay 400 causes relay 401 to operate in an obvious circuit.

lVhen relay 213 operated as above described, extending the talking conductors throughto the link circuit, relay 431 operated in a circuit from battery, lett Winding of lrelay 431, outer lett back contact of relay 439, lett normal contact of relay 437, conductor 205, innermost upper contact ot .relay 213 through the trunk linder, conductor 10G, ring of jack 104 and plug 112, through the usual polarized relay (not shown) ot the A operators cord circuit, tip of plug 112 and jack 104, conductor 105, `through the trunk inder, next to the innermost up- )er contact ot relay 213, conductor 204, right normal contact ot relay 437, right Winding of relay 431 to ground. The operation of relay 210 opened the energizing circuit of relay 400, but relay 400, being slowto-release, remains energized long enough tor relay 431 to operate and close a locking circuit for relay 400 over its lett front contact to ground at the front contact otv relay 400.V Relay 400 holds relay 401 operated. Since the operation of relay 401 is necessary to close switch setting conductor 233, the extension ot the connection is now in part under the control of the A operator.

llVhen relay 202 operated to start the trunk finder, relay 403 opera-ted in a circuit which may be traced from grounded battery, through Winding of relay 403, conductor 236, front contact and grounded armature ot relay 202, closing the position iinder start circuit. Relay 500 operates in a circuit which may be traced from grounded battery, Winding of relay 500, conductor 532, normally closed contact of relay 529, conductor 533, right back Contact ot' relay 520, lett back contact ofrelay 508, conductor 534, lett middle Contact of relay 403, conductor 352- to ground in the position circuit. Operated relay 500 connects ground from its right Contact to the Winding ot relay 501 Which thereby energizes. Relay 501 operated closes an energizing circuit for operating stepping magnet 502 ot the position finder which may be traced from grounded battery, Winding of stepping magnet 502,fconductor 533, normally closed contact of relay 508, conductor 537, contact and armature of magnet 404, conductor V538, contact or" stepping magnet 502, Winding ot relay 503, inner right Contact of relay 501,

conductor 539`to ground at the inner lett contact of relay 403. Relay 501 operated thus closes a path tor operating relay 503 and prepares a locking path for relay 504 over its lett front contact to ground at the bach contact of relay 505. It the terminal on which the test brush 527 of the position linder is resting is grounded indicating that the position is busy or vacant, a shunt is closed around the Winding ot relay 503 extending over the outer right contact ot relay 501, lett back contact ot relay 503, inner right back contact ot relay 509,'brush 527, to grounded conductor 507. The stepping magnet 502 Will operate its armature and interrupt its own circuit causing the switch brushes to advance one step. This action Will continue until anidle terminal is found. lllhen an idle terminal is found, relay 503 Will operate from battery through the stepping magnet in the circuit hereinabove traced, close a testing circuit for relay 505 through to lead 50G. Relay 503 operated, also grounds test lead 507 and closes a path tor operating relay 504. Under this condition itl there is only one switch testing a terminal, relay 505 W`ll operate to open the path for operating-relay 504. Relay 505 operated, operates relay 508 in a circuit which may be traced from grounded battery, Winding ot relay 508, right outer back contact of relay 509, conductor 540, front contact of relay 505 to ground. The operation ot relay 508 opens the energizing circuit tor relay 500 which Will restore to normal, causing relays 501 and 503 to release, thus opening the energizing circuit for relay The deenergization 'of relay 505 opens the circuit for energizing relay 508. Under this condition, relay 508 Will. loch through ,its lett middle Contact, the winding or' relay 509, conductor 539 to ground at. the innermost lett contact ot relay 403. Relay 509 is energized in this circuit and will in turnoperate relay 510 in a circuit which may be traced from grounded battery, Winding ot relay 510 through the lett trent Contact oit relay 509, conductor 541, right back contact ot relay 405, outer left bach contact ot relay 406, conductor 407, middle contactof relay 401, inner right contact or" relay 403, conductor 237 to the middle grounded armature of relay 210. Relay, 508 operated, connects the guarding ground to test brush 527 the posit-ion finder in a circuit which may be tracedy from ground, right middle Contact. of relay 403, conductor 408, right back contact of relay 542, conductor 409, back contact of relay 406, conductor 543, left contact ot relay 508, to testbrush 527. Relay 508 operlll) ojl'icrated, transters the testcircuit troni lead 500 ot the position selector to lead 410 ot the render selector over its outer right trout contact. It also closes the talking leads 514i.

and 515 to the B opcrators position (Fig. I3) and closes the start lead 410 to relay` 500,

This start circuit tor relay 500 may he traced troni hattery` through the Winding of relay 500, right norn'ial contact of relay 520, iliner right front contact o1'v relay 510, right inner contact ot relay 511, conductor 410, through the right contact of key S05, to ground at the right haelt contact of relay 802 ot any idle sender in the group. As before, relay 500 operates relay 501 and relay 501 closes the circuit for the sender selector magnet 404.

The circuit ot the sender selector stepping niagnet 404 niuy he traced from battery through the Winding ot the magnet-` right alternate contact ol relay 508, back contact o1 inagnet 404, back contact et magnet 502,

and thence in parallel through the Winding of relay 503 to grounded conductor 539 and over the outer right front contact ot' relay 501, left hack contact of relay 503, inner right trout contact of relay 509, to conductor 41T, brush 414, conductor 415, left contact ot key S05, to the front contact o1. relay S07 whichwill be operated if the sender is busy. ln the euse ot a busy sender, however, relay 503 is shunted as in the case ota busy position and magnet 404 operates, opening its own circuit and advancing the sender selector to the next sender. llVhen an idle sender is found relay S07 will not he operated and no shunt will he closed around the `winding of relay Relay 5023 in ol'ierating connects ground over its inner le'l't front contact, to brush 414 to niark the sender husy to other sender selectors.

Relay i-l will also close a circuit :from grouiuil at the back contact o1 `relay 504 through the Winding of relay 505, outer right lront contact ot relay 503, outer leit` front contact ot relay 510, inner riglit nornial contact of relay 517, conductor 419, brush 427, conductor 418, right hack contact of relay 802, resistance S to battery. Relay 505 operates in this circuit and closes a circuit i'roni battery through the winding of relay 511. outer right 'trout contact of relay 509 to `ground at the 'front contact of relay 505. Relay 511 operates and closes a locking circuit ior `itself over` its outer left contact, Winding o1 `relay 517 to grounded conductor 408. as lietore the operation of relay 503 closed a circuit for slow-tofoperate relay 504 which when it opcratesopensthe circuit of relay 505 which when it operates opens the circuit for relay 504. rlhe operation of relay 511as previously described opens the circuit ot relay 500, restoring that, relay andrelays 501 and 503 to normal. The release ot relay 505 when its circuiti is opened by slow-to.

he traced troni grounded battery, through winding` ot relay 511, outer leittront contact oit relay 511, conductor 544, Windingiof relay 51T, outer left` iront` contact of relay 517, conductor 411, lett trent contact of relay 410, coi'iductors 413, 408 andY 412 to the iniddle right liront contact of relay 403. Relay 511 operated; also opens the start lead andthe circuit of the control relays of the sender selector at itsouterinost right armature and prepares a circuit l'or relay 520 which inay be traced from grounded battery, right back contact oit relay 540, conductor 547, Winding ot relay 520, inner lett `front contact ot' relay 511, conductor 54S, to ground at the outer hack contact of `relay 410. Relay 517 operated connects leads 521, 506 and 522 troni the position finden to the corresponding leads 4119, 420 and 401 from the sender selector. Relay 410 operated connects the pulsing leads 233, 234 from the trunk finder (Fig. 2) to the sender selector pulsing leads 421 and 122. Relay 410operated, also opens its lett and right outermost contacts tor con trolling relay '20 and locks to the control ground supplied hy relay 403.

llllien the Bi position is seized relay 300 will operate in a circuit which may he traced troni ground at the outer lett back contact ot relay 540, conductor 550, let't Winding of relay 542, middle left front contact ot relay 510, position linder brush and Contact 551, conductors 515 and 310througli the winding ot'` relay 300, conductors 311 and 514 to the contact and brush 552 ot theiposition finder, outermost lett trout contact of relay 510, right Winding ot relay 542 to grounded battery. Relay 2300 operated,` operates relay 301 in a circuit which may be traced from grounded battery through the Winding of relay 301 to groiuid` at the right front contact ot relay 2300.

Vllhen the B operator inserted her headsetplug into jacks 313 and 380 a circuit was closed frein battery through the Winding of relay 350, tip of jack 380, through the telephone-headset, tip of jack 313, right winding of induction coil 351 to ground. The operation of relay 350 disconnects the ground which marks the position vacant from the test lead 507. It also prepares a test circuit from conductor 507, over its left front Contact, and connects ground over its right front contact, right back contact of relay 301 to conductor 352 for the purpose previously set forth. Then now the position finder connects with the position and relay 508 operates connecting ground to brush 527, a circuit is closed from bat-- tery through the winding of relay 314, right back contact of relay 353, left front contact of relay 350, conductor 507, to ground at brush 527. Relay 314 in operating supplies ground to the numerical keys and other parts of the circuit for controlling the position apparatus. It also closes an obvious circuit for operating relay 354. Viith relays 301 and 354 operated, lamps 302 and 303 are lighted, lamp 302 over the inner right front contact of relay 354 and the outer left front contact of relay 301 to ground; lamp 303 over the right back contact of relay 319 and the left back contact of relay 306 to ground at the outer right contact of relay 354. The lighting of these lamps identities the trunk over which the call is incoming.

Relay 354 also closes an operating circuit for relay 353 extending through the winding of that relay, left front contact of relay 354, outer right front contact of relay 301 to ground at the right contact ofrelay 350. The operation of relay 353 disconnects relay 314 from the test lead 507 but relay 314 is held operated by ground over the inner left contact of relay 301. Relay 353 connects ground over its outer right front contact to test lead 507 tov mark the position busy. It also closes a locking circuit for itself to ground over its middle right contact. and the left contact of relay 354. Over its inner right contact relay 353 connects ground through the winding of relay 355 to battery at the left normal contact of relay 356.

rhis position circuit is arranged t0 transmit two short impulses of tone to the A operator to notify her that the B operator is ready to receive the number. rIhe first tone is transmitted as soon as relay 301 operates due to the closure of a circuit fromy 'source of tone over the inner right front contact of relay 301, back contact of relay 357, right back contact of relay 358, lower winding of repeating coil 359 to ground. This induces the tone in the upper winding of repeating coil 359 which istransinitted over the back contact of relay 356 toy conductors 514 and 515 and thel A '-operators position. The operaliOn of re- VterVal.

lay 355, which is described above, closes Y a locking circuit for itself from battery over its right alternate contact and also closes arcircuit from battery over the normal contact of relay 356, left back contact of relay 357, winding of relay 358 to ground at the left contact of relay 355. As soon as relay 358 operates it opens the tone circuit and the tone ceases in the A operators headset. It also closes a circuit from battery over its right alternate `contact through the winding of relay 357 to ground at the left contact of relay 355. Relay 357 locks over its inner left front contact, to battery at the normal contact of relay 356 and opens the energizing circuit of relay 358. Then relay 358 closes its back contact, a circuit is again closed from the source of tone, this time over the right front contact of relay 357, left contact of relay 358, lower winding of repeating coil 359, to ground and a second tone is transmitted to the A operator.

The release of relay 358 wit-h relay 357 operated closes a circuit from battery over the right normal contact of relay 358, outer left frontcontact of relay 357, winding of relay 356 to ground at the left contactof relay 355. Relay 356 closes a locking circuit for itself over its left alternate contact and connects the talking conductors 515 and 514 through to the B operators headset. Relay 356 is slow-to-operate and does not cut olf the tone'until after a measured inr)The slow release and slow operating character of relays 356, 357 and 358 serves the purpose Vof measuring the length of the tone and the interval between tones.

When the pulsing leads where connected through to the sender by the operation of relay 410 as previously described a circuit was closed from battery through the winding of relay 151 in the lirst selector, inner left back Contact of'relay 152, conductor 153, through the trunk linder, next to the uppermost front contact of relay 213, conductor 234, middle right contact of relay 410, conductor 421, through the sender selector to conductor 425, winding of relay 881, outer right back contact of relay 809, inner rightback contact of relay 825, conductor 426, through the sender selector, conductor 422, inner right front contact of relay 410, inner right front Contact of relay 401, conductor 233, uppermost contact of relay 213, through the trunk finder, conductor 154, outer left back contact of relay 152, left winding of relay 151, contact- 155 to ground. Relay 881 operates in this circuit and closes an obvious circuit for operatingrelay 882.

Relay 882 in turn operates and closes an obvious circuit yfor relay 803. Relay 803 in operating connects battery over its kleft Y front contact to the register relays, and connects ground over its right front Contact n nl liti

sender is ready to receiverees andi thi` haok eonlaet oit relay S09, to Coinplete the holdingr eireuit of Certain relays as will hereinafter appear. It also closes anohyious eireuiti'ori operating relay 80T. RelaySOTeonneets ground over its right front. Contact and thelelt eontaet of hey 'S05 to testl-ead All() niarltinlhY the sender busy. It also closes an olivioue circuit for relaySOlwhich diseonneets `eround troni eoinluetor Lllo and dieronneets hattery :troni conductor ellS. Al its right front contact relay 802 eonneets eonduetor ll to relay 88B.. `As soon as relay S023 operated, con ineeting: ground to eonduetor (ill), relay titl() operated in a erenitlfri'nnhattery through its winding, outer lett haelt Contact of relays; `(S03, (304i, (3()5,`(tl($and GOS, eonduetor G09 to `Lrounded Conductor 610. (Vith relay G() operated, a circuit is Closed troni hattery over the left` 'lionteontziet of relay 80S, eon- `duetor (H214 tlnoualrthe right winding ol" relay (51:25; outer right iront eontarl; ot' relay GOO, conductor (32th Windingl ot relay 884, eonduetor 424, sender seleetor hrush EFL conductor lGlQ inner l-el'tt'ront contant of relay l'ilyposition selector lnush 5585 een duetor 29, outer left` haelt Contact of` relay 305. `windingY oli'elay Ril-h Conductor 3'15, right haek eontaet ot' relay llt, normal een taet ot" relay SlS to ground atA the right front eontaet ot relay Slal.

r Relay Bull operates i1r this eireuit hat relaysetlli'l and Sill donot. llelay iltll eloees a eireuit troni grounded eonduetor llo over its front `eontaet1 .lett heel; eontaet ot relay l1f),`\rindin;;" of relay 80G to hatte y. Relay 306 operates und locks over its inner left Contact "to grounded Conductor SlT). The operation ol relay lo `enteiuls conductor tltl to" thenunierieal keys. Tt also Closes a Circuitlfroln hattery through the winding ol? relay 805, niiddlelelt Contact o'f relay Slo to- `rroiuided Conductor Slo. lln additionllitopens the eli-Cuit ol" the white lamp 303 indieatinej to the B (nieral'or that the lations.. The, operation ot' relay 305 extends eondnetors 521 ando@ through to the nuineiiral ,hej/'5.2. Itxnay he noted that eonduetors F-iand Ml `are extended through resistance coils so as to componente for the in'esenee of relay 555 in conductor tlt. i'lliefiiperation ol relay 305 opens the elrenit olrelay Stiland that relay releases. Then the Iloiierator presses the inunerieal keys corresponding to theinuniher given heroy` the A operator, she will ronneet direct ground or `ground through r` :tanees :lill andllilito leads htll, lland `delnndent on wlneh keys are pressed.

F ll` ng 1s i `tilole in'liritlng' lli reli tlonship between `the `keys of the B operators l key` set. the conductor `to which `ground is appledand the nature of that fground (whetherdireet or through a resistance), land the relay or relays operated thereby inthe lirstfregister. The` relays ot the various registers are similarly located, so thatWt-he Correspondence between a key a n d the proper relay ot a particular register may easily he determined.

Key. Conductor. Resistance. Relay.

1 521 None 613 5()( 321 625 Bill None 613 l 521 'None G13 o None 325 8 50G None (52:3 624 522 N one (513 i (A6 l 50e None (325 (l2-l 522 64o 0 een 321 (325 522 322 646 In therese `ot keys 4 ando the connection oil'iground to conductor llthrough resistance serves to bring,` about the( transfer tronr one register to the next as will he pointed out hereinafter.

Should the ll operator press one or niore of the numerical keys before the lamp 303 is extinguished (which indicates that the Sender has not` yet been attached, at which tinte relay 305 will not he operated),I relay Boelwill operate in a eireuit which may he traced from` grounded hatteryorer the inner left or outer right hack eontaetiol relay 305, through retardation eoil SGO and 361 over the hael-I contact ot' relay 362 or 363 oyerthe contacto-t one or more of the numerical keys*v thrrnijrh the .winding of relay 364; to

`groinnl at the right :liront Contact of relay Relay 36411 operated closes a circuit tor tilde. relay lll() through its Winding over the liront eontaet ot relay lt'll left haelt Contact ot relayilt to ground at the right front Contact oi: relay lil. Relay looks over its lett troni; eontaet to its energizing Circuit independent oli relay loft land Closes` a Circuit for lmnp 302% over its right front. Contact, to gfroun-l through interruptor let-Vl. lllhen the render attached the, falender indicator lamp 23u-il will he extinguished as explained hereinahove.

Relay SOIE when operated as previously de eerihed eloeed :i circuit extending 'lj'roin hattery, through the winding of relay 813, le'lt haelt Contact of: relay 82h, Conductor 8? l,` to grounded eonduetor G10. Relay 8l?) opell` atesand `eloses an obvious circuit for relay 814.

Assuming' `that the wanted nlnnher `is 2603 the illl operator will tir-st depress numerical key 2 representing th'e irst'digitof the i called number, relays 883 and 613 Will operate in series in a circuit which may be traced from grounded battery, conductor 612, through the Winding of relay 613, outer right front contact 'of relay 600, conductor 620, Winding of relay 883, right front contact ot' relay 802, conductor 418, contact and brush 427 of the sender selector, conductor 419, inner right front contact of relay 517, conductor 554, brush and Contact 553 ofthe position selector, conductor 521, inner left front .Contact of relay 305, retardation coil 361, back contact of relay 362, through the right closed contact of operated key`2, conductor 325, right front contact of relay 305, to ground at the right front` contact of relay 314. Sinceidirect ground Was connected to the circuit of relay 613 by key 2, relay 613 will operate and lookin a circuit from b-attery over the inner right back 'cont-act ot relay 809, conduct-or 632, inner right front contact of relay 600, left Winding of relay 613, inner left front contact ot' relay 613 to ground. lRelay 883 operated, operates relay 614 in a circuit which may be traced from grounded battery through the Winding ot relay 614, left outer front contact of relay 600, conductor 621 to ground at the right outer `front contact of relay 883. Relay 614 operated, locks over its inner right contact, winding of relay A603, conductor 609 and grounded conductor 610. Relay 603 does not operate, being shunted bythe operating circuit tor relay 614. Relay 614 also closes a. circuit for operating relays 619, 812 and 816. This circuit may be traced from grounded battery through the right back contact of relay' 826, left Winding oit' relay 812, inner left back contact of relay 817, conductor 622, left front contact of relay 614, conductor 623, right back contact of relay 625, right front contact of relay 613, winding ot relay 619, conductor 626, through the Winding of relay 816out-er left back contact of relay 818, conductor885, front contact ofrelay 814, to ground over conductor 834. Relay 812 locks in a'circuit from battery vat theiright' back contact of relay 826, right winding and innerv right armature ot i relay 812 to grounded conductor 834. Re`

lays 619, 812 and 816'are employed in establishing'the connection and Will be discussed hereinafter.

`When numerical key 2 is released by the B operator, relay 603 operates in the locking circuit of relay 614 since the release ot key 2 permits relay 883 to release.

The operation of relay 603 opens the energizing circuit for relay 600 whereupon rela-y 600 releases. Relay 603 operated, operates relay 700 in a circuit Which may be traced from grounded battery through the Winding of relay 700, conductor 627, outer l left front contact of relay 603,

outerV vlett back contacts ot relays 604', 605, k606 and 608 to grounded conductor 609. The operation of relay 700 places the sender circuit in position to receive registration on the second set of register relays. It may be noted that with relay 614 operated the locking circuit of relay 613 extends from ground over the inner left front contact of that relay over the left front contact and left Winding of that relay, out-er right front contact of relay 614 to battery over conductor 632 maintaining the locking circuit after rela-y 600 releases. v

When numerical key 6 is depressed representing the second digit of the called number, relay-712 Will energize in a circuit Which may be traced trom grounded battery over conductor 612, through the right windings of relays 770 and 712, inner right contact of relay 700, contact of relay 608, conductor 423, brush 428 of the sender selector, conductor 420, through the Winding ot' relay 555, outer right-frontcontact otrelay 517, through brush and contact 556 ot' the posi'v tionselector conductor 506, right tront conytact of relay 306, conductor V328, through the contact of operated key 6, conductor 329,

through` resistance 321, conductor 325V to ground at conductor 325. Relay 770 does not operate in this circuit due to the presence ot resistance 321 in the circuit. Relay 712 locks'in a circuit from battery onconductor 632, through the inn-er lett front contact of relay 700, lett Winding and inner let't front contactoil relay 712 to ground.

The operation ot key 6 also closes a circuit from grounded conductor 325A over the right co-ntact of key 6, back contact of relay 363, through retardation coil 360, outer lett front contact of relay 305, conductor 52.2, brush 558, ot the position selector, inner lett front contact of relay 517, conductor 461, brush 429 of the sender selector, conductor 424, Winding of relay 884, conductor 620, outer right front contact of relay 700, right Winding of relay 711 to battery over conductor 612. Relays 884 and 711 both operate. Relay 711 locks in a circuit from battery on conductor 632, inner left front contact of relay 700, left Winding and inner lett front contact of relay 711 to ground. Relay y884 closes a circuit from battery on conductor 632, over the inner left front contact of relay 700, yWinding of relay 701, conductor 707, middle left front contact of relay 700, conductor 628, outer right front Contact of relay 884 to ground. Relay 701 locks over its lett Vfront contact to ground. Relay 884 in operating also closes a circuit from battery through the Winding of relay 615, conductor 629, outer lett liront Contact of relay 700,v inner right front Contact of relay 884 to ground. i j

Relay 615 locks in a circuit over its right Contact, Winding ot' relay 604, to grounded comluclor (309. Relay 60a (lees not operate in this circuitheing shunted by the operat-` ing ground tor relay (515;

When numerical key (i is released by the oliierator` relay' (504 operates in series with relay (315. The operation ot relay (ill-l opens the energizing circuittor relay TOO at its outer leil't back contact whereupon relay TUO rele-aises.` llelay (all operated also cle s an energizing' circuit tor relay T02 which may be traced troni ,a'rounded battery through the winding;r ol relay T02. conductor (530, enter lett liront contact olE relay Gllfl, through the outer lett back contacts ol relays (ll, 60G and GOS to grouniled conductor (all). lhe operation ol. relay 702 places the sender circuit in poi ltion to receive registretion upon the third set ot register relays.

lVhen `the numerical key l) is pressed by the ll operaton relay TF2 will operate in a circuit which inay be traced. 'troni grounded battery, on coialuctor 6l, right windings oit relays 772 and 703, inner right trent contact ol relay T02? conductor (531, inner right back cont` 4t o'l relay GUS, conductor 4255, contact: and brush 1,128 ol" tl e sender selector, contliutor 4120, winding of relay 555, outer right contact. olf relay all, conductor 55T, hrueh and contact 556 o'l the position se lector.` coiiiduci'or 50G, right liront contact oli relay 306, conductor 328, right contact ol' operated numerical hey resistance 532i, conductor to ground. Relay` 703 will not operate `in thi circuit due to the presence therein ot resistance 321. Relay '722 locks in a similar circuit to that ot relay G18. Relay 88a will operate in a circuit which may he traced :troni grrounffled battery on conclut`- 'lor 6.1.2, .right winding` ol relay 771. outer richt mintact oli relayv Tlllrconductor (S20, windingo'l: relay SSTL. conductor 42a,` contact and brush 4129 et `the sender selector, conductor 61, inner lett front Contact` ot relay 51T, brush and Contact 558 oi' the position selector, conductor 522, outer leftt'ront contact ol relay $305, retardation coil 360, back contact ot relay 36?, conductor 330, to the lett contact ot' operated numerical key 0a through resistance 322, coluluctor 325 lo ground. Relay T71 will not operate in this circuit due to the series resistance 322.

Relay SS4- (iflosc` a circuit lroin battery on conductor G32, inner left contact ol" relay T02. winding et relay TlSl, uiiddle lett contact ol relay 702, ctnidiulor (528 to ground at the outer contact ot relay 88a. Ilelay T19 locks over its lett armature to ground.

vlelay Glo peintes-in a circuit which may be traced from @rounder hatterythrough the winding ot' relay G16, conductor 633, outer le'l't :freut contact oit relay T02, conductor G21 to `around at the inner contact of relay S554. llelay tlG locks through the winding of relay 605. to ground conductor 609.

ll' hen the B operator releases numerical key (l, relay (50h operates in series with relay (S16. The operation of relay 605 opens the energizing circuit et relay 702 at its outer lett back contact, whereupon relay 702 releases. Relay (505 operated causes relay TG5 to operate in a circuit which may be traced from `grounded battery through the Winding ol? relay 705, conductor (33a, outer lett :trent Contact ot relay `($05, outer lett hack contacts oll relays (S06 and (SOS to ground at the lett front contact ot relay lll in a circuit similar tothat traced. in the operation el? relays 700 and T02. The opera tion ot relay T05 places the sender circuit in position to receive registration on the lfoifrth set ol register relays.

lllhen the numerical key 3 representing the tourth and last digit ot the called number is pressed by theVl' operator, relays TF3 and 'fl operate in series in a circuit which niay he traced troni grounded haton conductor (312, through right windi of relays 77a; and W35 inner right con tact ol relay 705, conductor 635, conductor (till, inner right bach contact ot' relay (30S, conductor 423, contact and brush 3l-28 ot the render selector, conductor 4:20, winding.;r ot relay 555, outer right front Contact ot relay 5l?, conductor 55T, brush and Contact et the position selector, conductor G, right 'lront contact ol relay 30G, conductor H28, through Contact ot operated numerical key S, conductor 325 to ground at the right trout contact et relay 314. Relays 773 and T74 locl .in a similar circuit to the locking circuit ol relay 61S.

A circuit is also closed from battery on conductor 612, through the right Winding of relay 775, outer right contact of relay 705, conductor C20, windingr of relay 883, right trent Contact ot relay SO2,` conductor 418, contact and brush 4127 of the sender selector, conductor 419, inner right front Contact ol" relay 517, conductor 554, contact and brush 553 ot the position selector, conductor 521, inner lett front contact of relay 305, retardation coil 361, `inner back Contact ot relay 362, right closed contact of numerical ltey 3 to ground over conductorBQ. Relays 775 and 88? both operate in this circuit, relay 775 lockinr lo ,aground over its inner left lront contact. Relay Gl' operates in a circuit which, may be traced .troni grounded battery throi'xgh the winding of that relay, conductor (3336, outernumt lcll' lront contact oit relay T05 to `round at the outer right ilront contact et relay S89. Relay 517 loclzs in a circuit over its richt contact, Winding ot relay GOG to grounded conductor G09.

1When numerical key l is released by the B operator, relay (50G operates in series with relay 61T. `The energizing circuit ot relay nT05 is opened by the operation ot" relay (306, whereupon relay 705 releases. The operation of relay 606 closes a circuit for lllll operating relay 608 which may be traced from grounded battery, inner left front contact of relay 606, left back contact of relay 607, through the winding of relay 608 to grounded conductor 609. The operation of relay 608 will connect ground to conductor 423 through its inner right front Contact and disconnect the B operator from the link circuit as will be hereinafter described.

As has been explained, the setting up of the first digit by the B operator, operates one of the relays 670, 619, 671, 672 or 673. 'I hese relays are provided with one or more armatures which, if the corresponding first digit represents a group requiring live digits, are connected to .grounded conductor 610. Relays 670, 619, 671, 672 and 673 operate individually when the register relays 613, 625 and 624 are operated in different combinations and in cooperation with the register relay 646 are eifective to operate the relay 607 to indicate that a iive digit number is to be recorded. For example, if the first digit registered is either two or seven, relay 19 is operated. If the'digit is two and it is desired to record ve digits for connections to all offices of the exchange designated by numbers whose first digit is two then the right armature of relay 619 is connected to conductor 610 for operating relay 607 and all the other armatures of this group of relays would remain unconnected. lf, however, the digit is seven and it is desired to record five digits the left armature of relay 619 is connected to conductor 610 and since for recording the digit seven, relay 646 `is also operated the circuit of relay 607 will be prepared. Thus the right armatures of relays 619, 67.1, 67 2, 673 and 670, if connected, will cause the operation of relay 607, if the irst digit recorded is either two, three, four, five or six respectively, and the left armatures of relays 619, 671 and 672, if connected, will cause the operation of relay 607,

if the first digit recorded is either seven, eight or nine respectively. In the drawing it will be noted that the left armature only of relay 672 is shown connected and thus a five digit number is recorded only when the first digit recorded is nine. rlhe operation of a relay whose armature is grounded, therefore indicates to the sender that the complete number of digits is to be iive, whereas the operation of any7 other relay indicates that the complete number of digits -to be set up will be four. l,The conversion of the four digit sender to a five digit sender is therefore effected by the operation of relay 607 due to the operation of the first digit relays having a grounded armature. rElie circuit of'relay 607Y mayV be traced from grounded battery through the winding of relay 607, conductor 639 to ground at the contact of the relay which corresponds e 'othe group reserved as five digit numbers.

The operation of relay 607 transfers the control of relay 608, which as has been previously noted, initiates the disconnection of the B operators position from the fourth digit, relay 617, to the ifth digit relay 618. rlhe Vdisconnection lof the B position is therefore delayed until after the reception of the fifth digit.

007115110X of switching operation.

It will be remembered that the registration of the first digit caused the operation of relays 812 and 816 in the circuit of relay 619 and that relay 812 locked to grounded conductor 834.

rlhe operation of relay 604 following the registration of the second digit closes a circuit for relay 824 which may be traced from grounded battery through winding of relay 824, outer right back contact of relay 825, outer left back contact of relay 821, left front Contact of relay 812, conductor 644, inner left front contacts of relays 603 and 604, conductor 643, contact of interrupter 822 torground. Relay 824 operated, closes an operating path for relay 825 and a locking path for itself which may be traced from grounded battery through the windings of relays 824 and 825 in series, right front contact of relay 824 to ground at the inner left back contact of relay 821 to grounded conductor 610. Relay 825 operated, removes the shunt around interrupter 823. Relays 824 and 825 are operated so as to insure against part of a pulse being sent out to the step-by-step switches over the leads 425 and 426.` The removal of the shunt by the operation of relay825 prepares for the operation of the switches in accordance with interruptions controlled by the counting relays.

rEhe circuit for operating first selector 150 was completed when relay 410 operated and may be traced from battery, right winding of relay 151, middle left baclr contact of relay 152, conductor 153, through the trunk finder, contact of relay 213, conductor 234,

' middle right front contact of relay 410, conductor 421, brush and contact of the sender selector, conductor 425, winding of relay 881, outer right contact of relay 809, c ontact of interrupter 823, conductor 426, brush andcontact of the sender selector, conductor 422, inner right Contact of relay 410, inner right contact of relay 401, conductor 233,' uppermost Contact of relay 213, through the.

trunk finder, conductor 154, outer left back contact of relay 152, left winding of relay 151, to'ground at contact of relay 155 at the first selector; Relay 151 operates and Acloses an obvious circuit for relay 156. Relay 156 prepares' an operating circuit for vertical magnet 157 which may be tracedr from battery through the winding Vof magnet 157,

winding ofy relay 158, inner front contact of interruiiter 822.

`ground at its hack contact..

relay 156, to the haci: contact el relay 161.

'In the sending.;r out of pulses for the irst digit set up (2), counting' relays S19 and S20 and correepondinrgrelaya 6. tl and 621 are operated to control the nunlher et interrup- "tions of the Switches operating the ereuit.

Relay S19 operates in a circuit which nlay he traced `from grounded hattery through the Winding ot relay 61), inner lelt 'liront contact otrelay 616` inner lett hach contact o1' `relay 81S, outer right contact ol: relay tra ing circuit lor iteell in series with relay S18 `which may he traced troni `aronnded hattery through the Windingot relay 819, iront contactot relay S19. windingl ot relay S16, outerlefthack Contact oli relay S11, conductor S85, :front contact olf' relay 611 to grounded conductor 831-. When interruptor 822 opens its contact relay 616 oyiierates in this circuit andopens the energizing circuit :for relays 616 and 619 'which rebase. Relay 812 does not release at this tinie .it is ,locked through its right winding;- and inner right front Contact to grounded. (,:ondurtor 831. It should he pointed out that when the contact of interruptor S22 is closed the contact oit interruptor S26 opens. There- `t'ore the circuit of relay 151 ie interrul'lted each linie that a pair ot' counting' relays is operated.

Upon the Second closure of the contact ot interruptor S22. countingr relay S26 will operate in a circuit which may he traced lroin grounded hattery, through the Winding ot relay S26. right hach contact ot relay inner lett front contact ol relay S18, outer rightilront contact ot relay and thence an traced lor relay 616 to the cloaed contact oli Relay 826 operated. locks in a circuit which may he traced troni grounded battery through the whirling ol .relay 89.0. front contact ot relay S26, wind ing oi relay 821 to grounded conductor 865. Relay S21 (nierated. releaaes relays and 825 hy opening its inner let't hach Contact. The release ol: relay n'ill reclose the shunt around interruptor S26 and thus prevent the further interrupting` ot the circuit of relay 151.

Atthe tiret openingl o1E the contact ot interrupter S26, relay 151 reliaeee completing: theeireuitahove traced `tor magnet 15T. to 'llhe operation of magnet 15T advances the tirst selector one vertical :stepn the Aaecond interruption olI the circuit ol' relay 1 61 y hy interruptor S951 cant-ica the advance oi the tiret @elector in a eec- `ond vertical step. Relay 156 operates in `the circuit et n'iaegnet 15T and heinel slow to release remains operated as long; as the circuit to relay 1531 is heine; interrupted. rl`he operation ot relay 156 closes a circuit from hattery through the winding of relay 159, olif-normal contact 166, 'front contact of re lay 156, outer iront contact of relay 156 to ground. Relay 159 loels in a circuit from battery through its winding, olli-normal contact 166, hachY contact ot magnet- 161, right iront Contact oi? relay 159, inner lett hack contact ot relay to `around. lllhen the release ol relay 825 closes the shunt around .interruptor S23, relay 151 remains operated long` enough to permit relay 156 to relez The release o1 relay 156 closes a circuit :troni battery, through the windingl ot rotary inagnet 161,` lett` i'ront contact ol. relay 159, norinal contact oi" relay 156. outer front contact ol' relay 156 to ground. lllagnet 161 operates and advances the switch one rotary step into engagementwith the lirst outgoing' trunk. lfifthiu trunk iahusyground will appear on the sleeve terminal engaged h v lirush 162. Aa soon aa niagnet 161 cloaca its hack contact relay 156 will he reoperated in a circuit extending' tln'ouefhv its winding', oil-nor mal contact 160, hack contact ot magnet 161, right hack Contact of relay 152, sleeve brush 162 to around. The operation ot relay 159 Will reclose the operating circuit for rotary magnet 161 and the switch will take another rotary step. The operation ot magnet 161 opens the circuit ol relay 159. As long as leleeve brush 162 encounters ground, relay 159 Will he reoperated after each rotary step and 'the switch advances. A aecond circuit ior relay 15S) also existe which n'iay he traced through, its rondine'.` ollnornlal Contact 1667 hack contact ot inap-net 161, winding1 ot relay 162, contact 168 to ground at the outer lront contactl ol.: relay 156. AS long); aS sleeve hrush 162 encounter-a y.frrounrh relay 152 is ahuntcd and does not` operate. Aa soon :ra an idle truuk is found eliaraeterized hythe ahsence of ground. relay opcratca. .lelay 159 heine' niarsrinal doce not operate in thiacircuit. The oiieration ot relay 152 extends the tip, ring and aleeve conductora through to the next Selector. ltaleo opens the circuit o1 line relay 1531 which relay re leaeee Vin turn releasing; relay 156. Hrm` v ever. relay 166 holds ita arinatnrea attracted 1er a timei thee niaintaininal around on the eleere conductor until the line relay and con reepondinja aloude-release relay of the'neai Selector hare operated to render hoth eclectors huisy.

The rrouni'l over eleeve hrueli 16?1 cora pletee a lochinir circuit tor relay 16:? which inay he traced itroln hattery. throue'h tht. winding' ot relay 156. olnoruial contact 166, hack fifontaet ol" niae'net 161, Winding; of re lay 152, contact 163, front contact oit relay hruah 1612 to ground.

The operation ol. relay 8:31, e previously deeerihed, cloaca the circuit ot relay 6.26

lfltl cuit.v Vond digit (G) will start at counting relay the Winding oit which inay be t'aced l'roni grounded battery, through'the Winding ol that relay over the iiinei lett trontfcontact ot relay 821K4 Yto grounded conductor 834. Relay 826 opens the energizingmcircuit or relayY 8l3at its left back contact. Relay 813 in turn releases relay 814. Relay 826 also reinoves battery roin the energizing circuit ol' relay 812 which releases. The releasel of relay 81%, releases countingrelays 818 and 819, 820 and821. Relays 603 and 81a release'due to the operation ot relay 826 which places battery on conductor 640. The release of relay 821 opens the energizing` circuit tor relay 826 at its left tront contact. Relay 813 releases when relay 6111 releases due to the opening'A or' the locking' `circuit of the latter ielay at the outer right front contact otrelay 614e. At the close ot any digit, thereifore, the operation Ot relay 826 releases the various register relays, Vand relays 812 and 81% a-rereleased and again operatedto provide an interval for the purpose ot allowing tiine for the switches toftrunlr hun `When relay 826 releases, relay 813 operates again in a circuit siinilar to that preiiously traced. Relay 814 will accordingly rcoperate.

hlt Will be reineinbered that the second digit set up was 6. Under this condition register relays 701, '711 and 712 were operated. Relay 827 therefore energized as soon as relay 603 released in a circuit `which inay be traced from grounded battery, through the winding ol' that rela-y, baclr cont-act ot,

relay 817, conductor 6541, through the right I" 4," L tient contact of relay (O1, conciuctoi sa lo ground at the outer right back contact of relay 603. Whenever the digit is gr ater than 5 alters the sequence ot the counting relays to cause their repeated operation to count inoretha-n live interruptions ot the switch control cir- T'ie counting for sending out the sec- 818 which operates in a circuit `which inay be tracedv from ground on conductor 834, front contact of relay 814i, conductor 885, outer leftbaclr contact ofrelay 817, vthrough relay 818, conductor 8127, outer right bach contacts ot relc y 770, right front contact of relay 711, outer leit -liront Contact ot relay 712, conductor 648,;outer lettk front contact of relay 615, right'back contact otrelayy Glllyconductor 622, inner lett back contact of relay 817, lett Wind: of relay 812, to battery at the right back contart of relay V826. vUpon the closure oit the contact of interruptor- 822 vwith relay 818 oifierated, an energizing circuit is closed ior At the saine tiine the iii-st opening of interrupter Contact 823 causes the second selector (not shown) 'to'y take a vertical ste Vllie eneroizin circuit for rela D b r .828 nia be traced troni Grounded batterv y f .l 7

The operation ot relay 827V through the winding of that relay, inner right front contact ot' relay V827, inner lett front Contact' of relay `8l8, outer right front contact of operated relay 825 over the circuit previously traced to the closed contact et interrupter'822.

Relay 828 operated will loch through its Alett front Contact in series Withthe Windrthrough the Winding orp that relay, lett back contact otre'lay 839, inner lett back con acts of relays 830, 816 and 818, outer right iront contact ot' relayv 825 and thence to the closed contact/of interrupter 822. Thus the second of the six pulses of the second digit will be counted. Y

Relay 829 operated, locks through its lett liront contact in series With the ufinding of relay 839 in a circuit similar to that traced for relay 819, relay 833 operating when in terrupter 822 reinoves the operating ground troni relay 829. Upon the third closure ot interruptor 822 with relay 839 operated. countingrelay 832 Willv operate in a circuit siinilar to that tracedor counting relay 819. rlhis Will coinplete the counting oi the third pulse to the second selector.

Relay 832 operated, Wil circuit for itself through its lett front contact in vseries with the Winding of relay 830, Which latter relay operates. rEhe operation of relay 830 Will open the energizing cir-l cuit for relay 839 and the locking circuit vtor relay 829, whereupon these tivo relays release. The operation-of relay 830 closes an `energizing path for relay 833 at its inner left front Contact and relay 833 operates upon the fourth closure of the contact of interruptor 822, counting the fourth pulse of the second digit 6.

Relay 833 operated Will close a locking circuit for itself through its lett iront contact in series with relay 816 Which relay operates. I'lh'e operation of relay 818 vill open the energizing circuit ot relay 830 and the locking` circuit for relay 832, whereupon these tivo relays will release. fifth closure of the Contact ot interrupter 822.y relay 819 will operate counting` the titth pulse to the switch.

Relay 81.9 operated, will Yclose a locking path tor itself lthrough its trent contact in series With the Winding or" relay 818 which later operates. rlhe operation of relay 818 opens the ,energizing pathV for relay 816 and Upon the Sill cle'e a locking tho locking path for relay 833, releasing these two last named relays. Upon the sixth closure of the contact of interruptor 22, counting relay 820 will operate and look through its lett front contactin series with the winding of relay which relay operates. This will count the sixth and last pulse ot' the second digit Ht up, namely 0.

The operation ot relay S21 releases relays S24 and S25. The release. ot relay S25 replaces the shunt around interruptor 021- which prevents the further interruption of the switch control circuit. lheoperation of relay Sill operates relay 820, the operation ot which releases relays `Sll and 014. Relays 015 and G04 will also release. l

The third digit zero `will be niarked on the countingI relays to determine at which point the operation ol the counting relays will begin in a manner similaito that described lfor the second digit. Relay 02T will at lirst be operated (the third digit also `being a number above whereupon thejlollowing pairs et counting relays will be open ated to `count l0 pulses: SHQBQ, SSL-030, sassur sepsis, ses-er?, e9- sae (0perated ilor the second time), SEQwSll), Sll-Sllh Sli) tl'lS, SllSQl. At the close oit the digit the operation oli' relay 821 causes sending to cease by the operation off relay S20. The various rrwister relays are caused to rel rase as described hereinalnne.

The l'ourth digit 3 will be marked on the countingl relays, the operation oi the counting relays beginning at relay S30. Relays Sl'lMS'lG, SlUMSlS, Sllml are subsequently operated in the course of sending out three pulses. Following the completion of the lastdigit, relay G08 releases initiating the release or the sender as will be hereina liter described.

Then the B operator releases the key correspondingto the last digit ot the nu1nher received from the A operator, and relaY (50S ope as previously described a circuit is closed from battery througli the winding oil relay 335, bark contact of relay 230i?. conductor 2328, right iront contact ol relay $300, conductor G, brush andcontact 550 ot' the position selector, outer right front contact oli relay 51T, winding of relay `555, conductor 490, brush and contact 49S olz the sender selector, conductor 423, inner right trent contact o't relay 00S to ground. Relay operates in this circuit in turn operating relay 549 by connecting ground to the winding ol relay 549 over its right front contact. `Relay 549 operated, opens the ground to relay 542 at its outer left back contact, thus opening the original energizing circuit for relay 542 and starting the release ol the position. Relay 540 operated, operates relay 406 in a circuit which may be traced from groi'inded battery, through the winding ol' relay 40G, inner lett front contact ot relay 549, conductors 559, 545, 408 and 412 to ground at the middle front Contact of relay 403. Relay 406 operated, .locks through its inner right front contact and closes a shunt around relay 517 which circuit may be traced `from battery through the winding of relay 511, outer right `liront contact ol relay 406, right back contact of relay 542 to grounded conductor 408. This circuit holds relay 511 operated and releases relay 517. The release of relay 517 opens the conductors connecting the sender and the position. Relay 406 in operating removes ground from the test brush 527 of the position selector; It also opens the energizing circuit of relay 510, whereupon relay 510 releases to disconnect the position 'from the conductors incoming from the A operator. `Relay 40G also closes a holding circuit for relay 555 at its outermost lett t'ront Contact. The operation of relay 549 also opens the circuit of relay 300 so that that relay releases in turn releasing relay 801. The release oi relay 301 closes a circuit from battery through lamp 302, inner right liront contact ol" relay 352, outer right back contact of relay 301, interruptor 341 to ground. Lamp 302 flashes in this circuit until the operation of relay 406 removes ground from conductor 507. The removal of ground from conductor 507 permits the release or' relay 314 which removes ground :lrom conductor 325; opens the locking circuit oit relays 300 and 319; opens the holding circuit ot relay 305; and opens the energizing circuit of relay 354. Relay 354 in turn releases relay 353 which opens the circuit ot relay 355 and in turn the circuit of relay356. The B operators position is now tree to care lor calls incoming on other link circuits.

It will be clear from the foregoing description that as soon as the operator has finished setting up a. number the sender will indicate to the link that the operation of the position has been completed and will bring about the disconnection of the link lrom the position al'ter which the position is free to he seized by another link.

Release` of the sender.

dien the sender linishes controlling the establishment of the connection, relay G08 releases, opening the circuit of relay 555 which releases in turn and opens the energizing circuit for relay 549. Relay 549 re-V 

